Watch the U.K. to Understand Delta

When the U.K. dropped all coronavirus restrictions on “Freedom Day,” July 19, critics called the move a “dangerous and unethical experiment.” Harsher critics called it “epidemiologically stupid.” At the time, cases in the country were still rising amid a Delta-fueled spike. Then, to nearly everyone’s surprise, COVID-19 cases started falling. This suggests that Delta hit a natural peak in the U.K. by mid-July—not because of Freedom Day, the effects of which are only just starting to show up in the data, but through some other mechanism.

Now, two weeks later, “the impact of Freedom Day is the big question,” says Paul Hunter, an epidemiologist at the when all are lifted in a highly vaccinated country. This is uncharted territory. What happens in the U.K. can raise the rest of the world’s hopes—or dash them.